Table 3.

Estimates of $R_{\mathit{\text{trial}}}^2$ weighted by trial size, associated standard errors (SE), and estimates of τ (or range of estimated τ_i) under Cox and copula surrogacy evaluation methods for the ACCENT trials.

	Estimate (SE)
	Cox	M0	M1	M2	M3	M4
${\widehat{R^2}}_{\mathit{\text{trial}}}$	0.928	0.874	0.864	0.852	0.930	0.930
SE( ${\widehat{R^2}}_{\mathit{\text{trial}}}$)	0.108	0.138	0.143	0.148	0.107	0.107
τ̂ or range of τ̂i	-	0.891	0.692	(0.540 - 0.789)	0.648	(0.482 - 0.753)